Stay-bolt for steam-boilers.



No. 675.935. Patented lune ll, I901. J. H. DAVENPORT.

STAY BOLT FOR STEAM BOILERS.

(Application fllsd Feb. 18, 1901.)

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UNITED STATES PATENT OFFICE.

JOHN H. DAVENPORT, OF OMAHA, NEBRASKA, ASSIGNOR OF ONE-HALF TO JOHN R.LOVVREY, OF SAME PLACE.

STAY-BOLT FOR STEAM-BOILERS.

SPECIFICATION forming part of Letters Patent No. 675,935, dated June 11,1901.

Application filed February 18,1901. Qerial No. 47,827. (No model.)

To all whom, it may concern.-

Be it known that 1, JOHN H. DAVENPORT, a citizen of theUnitedStates,residing at Omaha, in the county of Douglas and State ofNebraska, have invented a new and useful Stay- Bolt for Steam-Boilers,of which the following is a specification.

The invention relates to improvements in stay-bolts for steam-boilers.

One object of the present invention is to improve the construction ofstay-bolts forsteamboilers and to provide a simple and com parativelyinexpensive one of great strength and durability adapted to provide amovable connection between it and the outer sheet of a steam-boiler,whereby all lateral strain on the head of the bolt will be prevented anda uniform tensile strain insured, so that breakage of a bolt will beeffectually prevented.

Another object of the invention is to prevent the inner and outer sheetsof a steamboiler from increasing or decreasing the distance between themwhen they expand under pressure and when the latter is removed.

The invention also has for its object to provide a construction of thischaracter which will admit of the employment of a telltale hole or borefor indicating breakage which may result from defective material.

The invention consists in the construction and novel combination andarrangement of parts hereinafter fully described, illustrated in theaccompanying drawings, and pointed out in the claims hereto appended.

In the drawings, Figure 1 is a sectional view showing a stay-boltconstructed in accordance with this invention and applied to the innerand outer sheets of a boiler, the bolt being shown in elevation. Fig. 2is a similar view, the outer end or head of the bolt being shown insect-ion and its inner end being riveted.

Fig. 3 is a detail perspective view of the cap.

Fig. 4 is a similar view of the bearing-sleeve.

Like numerals of reference designate cor- 5 responding parts in all thefigures of the drawings.

1 designates a stay-bolt designed to connect the inner and outer sheets2 and 3 of a steamboiler and provided at its outer end with a round heador ball 4 and having its inner portion 5 threaded for engaging athreaded opening of the inner sheet 2 of the boiler. The inner threadedportion 5 of the bolt is extended and provided at opposite sides withnotches 6, and it has a polygonal extremity 7, adapted to receive awrench for screwing the bolt in place, and after the parts have beenassembled the extended end of the bolt is cut off and is upset againstthe inner face of the inner sheet to form a head 8 for riveting theinner end of the bolt.

The head of the bolt is arranged within a socket 9 of a bearing-sleeve10, having exterior screw-threads 11 for engaging a threaded opening ofthe outer sheet of the boiler and also to receive a cap 12. The innerend or bottom of the socket is rounded to provide an annular concavebearing-surface to conform to the configuration of the inner portion ofthe round head or ball of the bolt which extends through the innor endof the sleeve, as clearly shown in Fig. 1. The exterior-lythr eadedsleeve is extended outward beyond the outer sheet, and, if desired,suitable jamnuts may be provided for clamping it against the outersheet.

The cap 12 is provided with interior screwthreads to engage those of thebearing-sleeve, and it has a central bearing portion 13 presenting aninner concave face to conform to the configuration of the outer side ofthe head or ball 4, and a metallic gasket or packing 14 is arrangedwithin the outer end of the bearing-sleeve. The metallic gasket orpacking 14, which may be lubricated by any suitable substance, is heldin engagement with the ball by the cap, and it presents an inner annularconcave face to the same. The cap is provided with an interior annulargroove 15, surrounding the central portion 13 and receiving the outerend of the sleeve. The concave bearing-surfaces of the cap and thesleeve and the gasket form a socket which conforms to the configurationof the ball or head, and a flexible connection or joint is providedbetween the bolt and the outer sheet of the boiler, whereby all lateralstrain on the bolt is eliminated and the uniform tensile strain iseffected, thereby reducing the liability to breakage to a minimum.

The bolt is provided at its outer portion with a longitudinal telltalehole or bore ex- ICO tending inward beyond the inner face of the outerboiler-sheet and adapted, should the bolt break through defectivematerial, to readily indicate such fact by the escape of steam or waterthrough the said bore or opening 16. The cap is provided With a centralaperture 17 of greater diameter than the bore or opening. The stay-boltis adapted to be applied to the inner and outer sheets oflocomotive-boilers and various other steam-boilers, and it is adapted toprevent the inner and outer sheets from varying the distance betweenthem When they are under pressure and when they are not subjected topressure. The bolt is subjected to the same strain at all angles, sothat it will not be broken by a lateral or twisting strain.

It will be seen that the stay-bolt is exceedingly simple and inexpensivein construction, that it is positive and reliable in its action inpreventing the inner and outer sheets from varying the distance betweenthem, and that a flexible or ball-and-socket joint is provided at thehead of the belt, which will permit the bolt to be arranged at an angleto the outer sheet Without being twisted or subjected to a lateralstrain. Furthermore, it will be clear that the head of the bolt bearsagainst the inner end of the sleeve and the cap, so that an equalbearing or support is provided at its inner and outer sides.

That I claim isl. The combination with the inner and outer sheets of aboiler, of a bearing-sleeve mounted on the outer sheet and provided witha socket, a bolt provided at its outer end With a ball arranged in thesocket, said bolt having a telltale-bore extending from its outer end toa point beyond the inner face of the outer sheet, and means for securingthe inner end of the bolt to the inner sheet, substantially asdescribed.

2. In a device of the class described, the combination with the innerand outer sheets of a boiler, of a bearing-sleeve mounted on the outersheet and having a socket, a bolt connected with the inner sheet andprovided at its outer end with a ball arranged within the socket, saidbolt having a telltale-bore extending from its outer end to a pointbeyond the inner face of the outer sheet, and a cap arranged on thebearing-sleeve and provided with an inner bearing-face to fit againstthe ball and having an aperture arranged at the outer end of the bore,substantially as described.

3. A device of the class described comprising a bolt having an innerthreaded portion and provided at its outer end with a ball, a sleevedesigned to be mounted on the outer sheet of a boiler and having asocket to receive the ball, a cap arranged on the outer end of thesleeve and having a central bearing and provided with an annular groovereceiving the outer end of the sleeve, and a gasket or packing arrangedWithin the sleeve at the outer end thereof and held against the ball bythe cap, substantially as described.

4:. In a device of the class described, the combination with the innerand outer sheets of a boiler, of an exteriorly-threaded bearingsleevemounted in a threaded opening of the outer sheet and provided with asocket, a bolt having a round head or ball arranged in the socket, aninteriorly-threaded cap engaging the outer end of the socket andprovided with an inner bearing-face fitting against the outer face ofthe ball, and a gasket arranged within the outer end of thebearing-sleeve and held against the ball by the cap, substantially asdescribed.

In testimony that I claim the foregoing as my own I have hereto aflixedmy signature in the presence of two witnesses.

JOHN II. DAVENPORT.

Witnesses:

J. A. THOMPSON, E. l[. VVARTNABY.

